This is a note to let you know that I've just added the patch titled
iio: adc: ad_sigma_delta: do not use internal iio_dev lock
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-testing branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will be merged to the char-misc-next branch sometime soon,
after it passes testing, and the merge window is open.
If you have any questions about this process, please let me know.
>From 20228a1d5a55e7db0c6720840f2c7d2b48c55f69 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nuno=20S=C3=A1?= <nuno.sa@xxxxxxxxxx>
Date: Tue, 20 Sep 2022 13:28:07 +0200
Subject: iio: adc: ad_sigma_delta: do not use internal iio_dev lock
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Drop 'mlock' usage by making use of iio_device_claim_direct_mode().
This change actually makes sure we cannot do a single conversion while
buffering is enable. Note there was a potential race in the previous
code since we were only acquiring the lock after checking if the bus is
enabled.
Fixes: af3008485ea0 ("iio:adc: Add common code for ADI Sigma Delta devices")
Signed-off-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
Reviewed-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Cc: <Stable@xxxxxxxxxxxxxxx> #No rush as race is very old.
Link: https://lore.kernel.org/r/20220920112821.975359-2-nuno.sa@xxxxxxxxxx
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
drivers/iio/adc/ad_sigma_delta.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index 261a9a6b45e1..d8570f620785 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -281,10 +281,10 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
unsigned int data_reg;
int ret = 0;
- if (iio_buffer_enabled(indio_dev))
- return -EBUSY;
+ ret = iio_device_claim_direct_mode(indio_dev);
+ if (ret)
+ return ret;
- mutex_lock(&indio_dev->mlock);
ad_sigma_delta_set_channel(sigma_delta, chan->address);
spi_bus_lock(sigma_delta->spi->master);
@@ -323,7 +323,7 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
sigma_delta->bus_locked = false;
spi_bus_unlock(sigma_delta->spi->master);
- mutex_unlock(&indio_dev->mlock);
+ iio_device_release_direct_mode(indio_dev);
if (ret)
return ret;
--
2.38.1
